32-SAMSS-037

Previous Issue: New Next Planned Update: 1 November 2016

Page 1 of 29

Primary contact: Mehdi, Mauyed Sahib on 966-3-8809547

CopyrightSaudi Aramco 2011. All rights reserved.

Materials System Specification 32-SAMSS-037 1 November 2011 Material Specification for the Manufacture of Fiber Reinforced Plastic (FRP) Tanks

Document Responsibility: Materials and Corrosion Control Standards Committee

Saudi Aramco DeskTop Standards Table of Contents 1 Scope................................................................. 2

2 Conflicts and Deviations.................................... 2

3 References........................................................ 2

4 Definitions.......................................................... 6

5 Raw Materials.................................................... 9

6 Laminates........................................................ 19

7 Inspection and Quality Assurance Requirements........................... 24

8 Documentation................................................ 27 Appendix A - Workflow for the Material Selection and Testing of FRP Tanks...... 29

Document Responsibility: Materials and Corrosion Control Standards Committee 32-SAMSS-037

Issue Date: 1 November 2011 Material Specification for the Manufacture

Next Planned Update: 1 November 2016 of Fiber Reinforced Plastic (FRP) Tanks

Page 2 of 29

1 Scope

1.1 This document covers the requirements for specification of and the acceptance

conditions for raw materials, properties, and testing of materials utilized for the

factory manufacture of fiber reinforced plastic (FRP) tanks, for use above

ground or underground.

1.2 The FRP tanks made of polyester, vinylester or epoxy resin system reinforced

with glass fibers, carbon fibers, or their combination, manufactured by the wet

lay-up and/or filament winding processes. Constructions both with and without

a lining of thermoplastics are included.

1.3 This specification applies to stationary tanks used for the storage, accumulation,

or processing of corrosive or other substances at pressures not exceeding 15 psig

external and/or 15 psig internal above any hydrostatic head.

1.4 The process for the material specification and quality control tests according to

this document is shown in flowchart, Figure A of the Appendix A.

2 Conflicts and Deviations

2.1 Any conflicts between this specification and other applicable Saudi Aramco

Materials System Specifications (SAMSSs), Engineering Standards (SAESs),

Standard Drawings (SASDs), or industry standards, codes, and forms shall be

resolved in writing, prior to submission of bids or start of related work, by the

Company or Buyer Representative through the Manager, Consulting Services

Department, of Saudi Aramco, Dhahran.

2.2 Direct all requests to deviate from this specification in writing to the Company or

Buyer Representative, who shall follow internal company procedure SAEP-302

and forward such requests to the Manager, Consulting Services Department of

Saudi Aramco, Dhahran.

3 References

Material supplied to this specification shall comply with the latest edition of the

references listed below unless otherwise noted:

3.1 Saudi Aramco References

Saudi Aramco Engineering Procedure

SAEP-302 Instructions for Obtaining a Waiver of a Mandatory

Saudi Aramco Engineering Requirement




Page 3 of 29

Saudi Aramco Materials System Specification

32-SAMSS-002 Manufacture of FRP Storage Tanks

Saudi Aramco Engineering Standard

SAES-D-110 Design of Fiberglass-Reinforced Plastic (FRP)

Storage Tanks

3.2 Industry Codes and Standards

American Society of Mechanical Engineers

ASME RTP-1 - 2007 Reinforced Thermoset Plastic Corrosion-Resistant

Equipment

American Society for Testing and Materials

ASTM C581 Determining Chemical Resistance of Thermosetting

Resins Used in Glass-Fiber-Reinforced

Structures Intended for Liquid Service

ASTM C582 Specification for Contact-Molded Reinforced

Thermosetting Plastic (RTP) Laminates for

Corrosion-Resistant Equipment

ASTM D638 Test Method for Tensile Properties of Plastics

ASTM D648 Standard Test Method for Deflection Temperature

of Plastics under Flexural Load in the Edgewise

Position

ASTM D790 Test Methods for Flexural Properties of

Unreinforced and Reinforced Plastics and

Electrical Insulating Materials

ASTM D2583 Test Method for Indentation Hardness of Rigid

Plastics by Means of a Barcol Impressor

ASTM D2584 Test Method for Ignition Loss of Cured Reinforced

Resins

ASTM D 3299 Standard Specification for Filament-Wound Glass-

Fiber-Reinforced Thermoset Resin Corrosion-

Resistant Tanks

ASTM D4097 Standard Specification for Contact-Molded Glass-

Fiber-Reinforced Thermoset Resin Corrosion-

Resistant Tanks

ASTM D5083 Test Method for Tensile Properties of Reinforced

Thermosetting Plastics Using Straight-Sided




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Specimens

ASTM E84 Standard Test Method for Surface Burning

Characteristics of Building Materials

European Standard

EN 59 Glass Reinforced Plastics - Measurement of

Hardness by Means of a Barcol Impressor

EN 29092 Textiles - Nonwovens - Definition

EN 13121-1 GRP Tanks and Vessels for Use above Ground -

Raw Materials - Specification Conditions and

Acceptance Conditions


Composite Materials - Chemical Resistance


Design and Workmanship


Delivery, Installation and Maintenance

International Organization for Standardization

ISO 75-2 Plastics - Determination of Temperature of

Deflection under Load -

Part 2: Plastics and Ebonite

ISO 178 Plastics - Determination of Flexural Properties

ISO 306 Plastics - Thermoplastic Materials - Determination

of Vicat Softening Temperature (VST)

ISO 472 Plastics - Vocabulary (ISO 472:1999)

ISO 527-2 Plastics - Determination of Tensile Properties -

Part 2: Test Conditions for Moulding and

Extrusion Plastics

ISO 868 Plastics and Ebonite - Determination of Indentation

Hardness by Means of a Durometer (Shore

Hardness)

ISO 1133 Plastics - Determination of the Melt Mass-Flow

Rate (MFR) and the Melt Volume-Flow Rate

(MVR) of Thermoplastics

ISO 1163-1 Plastics - Unplasticized Poly (Vinyl Chloride)

(PVC-U) Moulding and Extrusion Materials -




Page 5 of 29

Part 1: Designation System and Basis for

Specifications

ISO 1183 Plastics - Methods for Determining the Density and

Relative Density of Non-Cellular Plastics

ISO 1887 Textile Glass - Determination of Combustible-

Matter Content

ISO 1889 Reinforcement Yarns - Determination of Linear

Density

ISO 2113 Reinforcement Fibers - Woven Fabrics - Basis for a

Specification

ISO 2554 Plastics - Unsaturated Polyester Resins -

Determination of Hydroxyl Value

ISO 2559 Textile Glass - Mats (Made from Chopped or

Continuous Strands) - Designation and Basis for

Specifications

ISO 2797 Textile Glass - Rovings - Basis for a Specification

ISO 3344 Reinforcement Products - Determination of

Moisture Content

ISO 3374 Reinforcement Products - Mats and Fabrics -

Determination of Mass per Unit Area

ISO 3915 Plastics - Measurement of Resistivity of Conductive

Plastics

ISO 6721-2 Plastics - Determination of Dynamic Mechanical

Properties - Part 2: Torsion-Pendulum Method

ISO 9073-1 Textiles - Test Methods for Nonwovens -

Part 1: Determination of Mass per Unit Area


Part 2: Determination of Thickness


Part 3: Determination of Tensile Strength and

Elongation

ISO 9771 Plastics - Phenolic Resins - Determination of the

Pseudo-Adiabatic Temperature Rise of Liquid

Resols when Cured under Acid Conditions

ISO 11357-2 Plastics - Differential Scanning Calorimetry (DSC)

- Part 2 Determination of Glass Transition

Temperature




Page 6 of 29

ISO 11359-2 Plastics - Thermomechanical Analysis (TMA) -

Part 2: Determination of Coefficient of Linear

Thermal Expansion and Glass Transition

Temperature

Underwriters Laboratories

UL 1316 Glass-Fiber-Reinforced Plastic Underground

Storage Tanks for Petroleum Products, Alcohols,

and Alcohol-Gasoline Mixtures

4 Definitions

4.1 General

For purposes of this specification only, the following definitions apply:

Carbon fiber: fiber produced by pyrolysis of organic precursor fibers, such as

rayon, polyacrylonitrile or pitch, in an inert environment.

Chelating agents: organic compounds which act by temporarily complexing the

organometallic accelerator out of the reaction medium. Example, acetyl acetone.

Chemical protective barrier: either the corrosion-resistant barrier or the

thermoplastic liner (if used), whichever will be in direct contact with the fluid.

Corrosion-resistant barrier: the composite material layer of the tank that will be

in direct contact with fluid, it is comprised of an inner surface and interior layer.

Crosslinking: process which bonds one polymer chain to another, to form a

tridimensional polymeric structure.

Cure/Post cure cycle: time/temperature/pressure cycle used to cure a

thermosetting resin system.

Cure: chemical reaction resulting in crosslinking of thermoset resin.

Curing agent: catalytic or reactive agent that, when added to a resin, causes

crosslinking.

Design Engineer: engineering company responsible for specifying design

requirements on the tank data sheet. It is also referred to as engineering contractor.

E-glass: a grade or type of glass fiber normally used to reinforce FRP tanks,

consisting mainly of SiO2, Al2O3 and MgO.




Page 7 of 29

Epoxy resins (EP): thermoset resin containing the oxirane (epoxide) reactive

group. Crosslinking occurs at these sites through addition of amines, Lewis

acids/bases and anhydrides. Examples, diglycidyl ether of bisphenol A,

diglycidyl ether of bisphenol F.

Fiber-reinforced plastic (FRP): plastic-based composite that is reinforced

with any type of fiber, not necessarily glass.

Glass transition temperature (Tg): temperature at which amorphous polymer

undergoes a marked change in properties on passing from the rubbery to glassy

state.

Gel coat: a thin layer of resin on the surface of a laminate that may or may not

be reinforced with a glass or a synthetic fiber.

Inhibitors: chemical agents which react with the curing system to slow down

the curing of the resin.

Initiators: generally organic peroxides which break down liberating radicals

initiating radical crosslinking process. Examples, Methyl ethyl ketone peroxide

(MEKP), Cumene hydroperoxide (CuHP), Dibenzoyl peroxide (BPO), acetyl

acetone peroxide (AAP), Cyclohexanone peroxide (CHP), etc.

Laminate: compilation of laminae of resin reinforced with fibers which are

fabricated during the manufacturing process of the tank. The laminate

constitutes the wall thickness structure of the tanks and their properties are

defined in Section 6 of this document.

Manufacturer: company responsible for the design, fabrication and testing of

tanks in accordance with this Specification. It is also referred to as Fabricator.

Maximum design temperature, Td: maximum temperature for determination

of the partial design factor, A2, as defined in EN 13121.

Maximum temperature, Tm: temperature given by the resin supplier or the

thermoplastics supplier referring to a specified fluid.

Organometallic accelerators: the primary agents which accelerate the

breakdown of the initiator to achieve a sufficient rate of generation of radicals.

Owner: Saudi Aramco organization which will utilize the tank and specify the

process requirements.

Post cure: the application of heat to take the resin crosslinking to a final stage.

Promoters: improve the reaction efficiency of the accelerators.




Page 8 of 29

Saudi Aramco Inspector: the person or company authorized by the Saudi

Aramco Inspection Department to inspect tanks to the requirements of this

specification.

Unsaturated polyester resins (UP): thermosetting resins consisting of

polyester molecules dissolved in a reactive monomer, typically styrene, capable

of copolymerization with the polyester.

Vinylester resins (VE): thermosetting resins consisting of phenyl- and/or

phenylene derivates (e.g., dialkoxy-bisphenol A), fumaric/maleic acid,

diisocyanate derivates and terminated with alkoxy-(meth) acrylate.

4.2 Symbol and Abbreviations

Symbols and

Abbreviations Units Description

HDT C Heat deflection temperature

MFR g/10 min Melt flow rate

t % Elongation at break in tension

f MPa Flexural strength

t MPa Tensile strength

ShD - Shore Hardness D

g/ml Density

Et MPa Modulus of elasticity in tension

Ef MPa Modulus of elasticity in flexure

CSM - Chopped strand mat

GRP Glass-fiber Reinforced Plastic

ECTFE - Ethylene-chlorotrifluoroethylene copolymer

FEP - Fluorinated ethylene-propylene copolymer

FW - Filament winding

PFA - Perfluoro-alkoxy copolymer

PP-B - Polypropylene, block polymer

PP-H - Polypropylene, homopolymer

PP-R - Polypropylene, random polymer

PVC-U - Polyvinyl chloride, unplasticised

PVDF - Polyvinylidene fluoride

WR - Woven rovings

CRL - Chemical Resistant Layer

VL - Veil Layer

TPL - Thermoplastics Liner




Page 9 of 29

5 Raw Materials

5.1 Resins

a) The resins used for FRP tanks are liquid or liquefiable, thermosetting in

nature and cured by molecule crosslinking (polyaddition or

polycondensation) with or without curing agents (initiators,

accelerators/promoters).

b) The resin supplier shall state in the resin technical data sheet the name,

type of resin, resin group and resin typical properties. Properties of UP

and VE resins are published in Table 1.

c) The tank manufacturer shall verify that the resin conforms to the property

values of color, viscosity, nonvolatile content and gel time as established

in the resin manufacturer technical data sheet.

d) Only resins with an HDT of at least 82C (180F) per ASTM D648 with a

1.8 MPa (264 psi) loading and a 3.2 mm (18 in) specimen shall be used.

e) The tank manufacturer shall verify resin meets the chemical resistance

requirements given in EN 13121-2.

Note: Orthophthalic acid based UP resins are not allowed to be used in the manufacture FRP tanks under this specification.

f) For the manufacture of fiber reinforced plastic underground storage tanks

for petroleum products, alcohols, alcohol-gasoline mixtures and Methyl

tert-butyl ether (MTBE), the resin systems shall meet the requirements of

UL 1316 Section 14.

g) The manufacturing procedure and cure schedule of thermosetting resin

laminates shall be in accordance with the resin supplier's

recommendations.

h) Most thermosetting resins require elevated temperature post cure to

enhance chemical and thermal resistance.

i) When required, flammability and electrical conductivity shall be taken into

consideration for the material to meet the requirements established in

Sections 6.1.6 and 6.1.7 of this document.

5.2 Curing Agents

5.2.1 Curing Agents for Unsaturated Polyester and Vinylester

a) The cure system supplier shall state the compatibility of the curing

system with the resins, give recommendations on the quantities and




Page 10 of 29

conditions of use and state any limitations on use in service.

b) The type and level of initiator to be used shall be compatible with

the resin system used and service conditions.

Table 1 Classification Scheme for UP- and VE-Resins

f

MP

a

min

90

75

12

0

11

0

10

0

11

0

13

0

13

0

13

0

a

Eth

yle

ne-

, 1

,2-p

rop

yle

ne-

, die

thy

len

e-,

dip

ropy

len

e-,

neo

pen

tylg

lyco

l,

1,3

-bu

tan

edio

l 1

,4-b

uta

ned

iol

and

corr

esp

on

din

g

hal

og

enat

ed

gly

cols

b

May

als

o c

on

tain

cy

clic

un

satu

rate

d h

yd

roca

rbo

ns.

c

Rel

ated

to

th

e su

m o

f th

e d

iol

com

po

nen

ts

t

%

min

2.0

1.5

3.0

3.0

1,5

2.0

4.0

3.5

2.5

t

MP

a

min

60

50

75

65

50

60

75

75

75

HD

T

C

min

82

90

11

0

90

90

11

0

90

10

5

12

0

Tg

C

min

85

12

0

14

0

12

0

12

0

13

0

11

0

12

0

15

0

Con

ten

t

of

styre

ne

mass

-%

max.

50

50

50

55

45

55

55

50

50

Typ

e of

aci

ds

Iso

ph

thal

ic a

cid

, H

ET

aci

d,

Eth

yle

ned

icar

bo

nx

yli

c

acid

s

Iso

ph

thal

ic a

cid

, H

ET

aci

d,

Eth

yle

ned

icar

bo

nx

yli

c

acid

s

Ter

eph

thal

ic a

cid

, H

ET

acid

, E

thy

len

edi-

carb

onx

yli

c ac

ids

Iso

ph

thal

ic a

cid

,

Eth

yle

ned

icar

bo

nx

yli

c

acid

s

Eth

yle

ned

i-ca

rbo

nx

yli

c

acid

s

Eth

yle

ned

icar

bo

nx

yli

c

acid

s

Met

hac

ryli

c-/A

cry

lic

acid

Eth

yle

ned

icar

bo

nx

yli

c

acid

s

Met

hac

ryli

c-/A

cry

lic

acid

Ty

pe

of

gly

cols

Sta

nd

ard

gly

cols

a,

b

Sta

nd

ard

gly

cols

a

Sta

nd

ard

gly

cols

a

Neo

pen

tyl

(min

. 80

mo

l-%

)c

and

a d

iol

wit

h a

t le

ast

on

e

seco

nd

ary

OH

-gro

up

(max

.

20

mo

l-%

)c

Bis

(h

yd

rox

ym

eth

yl)

-

tric

ycl

od

ecan

Dip

rop

ox

y-B

isp

hen

ol

A

(min

. 90

mo

l-%

)

Ep

ox

idis

ed B

isp

hen

ol

A

Dia

lko

xy

- B

isp

hen

ol

A

(min

. 90

ml-

%),

Alk

ox

y

(met

h)a

cry

late

Ep

ox

idis

ed-N

ov

ola

k

Res

in

Ty

pe

UP

UP

UP

UP

UP

UP

VE

UV

E

VE

Res

in

Gro

up

2A

2B

3

4

5

6

7A

7B

8




Page 11 of 29

c) Organometallic accelerator usually used is cobalt naphthenate or

cobalt octoate.

d) Promoters are typically Dimethylaniline (DMA), Diethylaniline

(DEA), dimethylacetoacetamide (DMAA). When used with BPO,

promotors can act on the peroxide without the need for

organometallic accelerators. DMA/BPO system is required, at

least, to manufacture the corrosion resistance barrier of tanks to be

in hypochlorite service.

e) Inhibitors are normally alkylated phenols (e.g., tertiary butyl

catechol - TBC) which react with free radicals to form more stable

and less reactive species. With certain resin grades (e.g., VE)

chelating agents are also used.

f) The tank manufacturer shall verify that all curing system

components conform to the property values established in the

supplier technical data sheet.

5.2.2 Curing Agents for Epoxy Resin

a) Four major types of curing agent can be utilized to crosslink epoxy

resin utilized in the manufacture of FRP tanks, and these include;

aliphatic, (cyclo) aliphatic or aromatic amine, and anhydride.

b) The maximum operating temperature for tanks manufactured out of

epoxy resin and the above curing agents are shown in Table 2.

c) The glass transition temperature (Tg) of the resin system shall be

20C above the maximum design and operating temperature.

The resin cure may be verified by a glass transition test using

differential scanning calorimetry (DSC), Heat Deflection

Temperature (HDT) or dynamic mechanical analysis (DMA).

Table 2 Maximum Operating Temperature for Tanks Manufactured out of Epoxy Resin as a Function of the type of Curing Agents

Curing Agent Maximum Temperature, C (F)

Anhydride 65 (150)

Aliphatic Amine 93 (200)

Cyclo-Aliphatic Amine 110 (230)

Aromatic Amine 115 (240)




Page 12 of 29

d) In each material data sheet(s), the material supplier shall state the

name and type of curing agent and the typical properties.

e) The tank manufacturer shall verify that the curing agent conforms

to the property values of color, viscosity, gel time and anhydride

equivalent as established in the curing agent technical data sheet.

5.3 Reinforcing Materials

5.3.1 General

Reinforcing materials shall be made from different types of textile glass

in accordance with Table 3. Special arrangement of reinforcing material

should be specified taking into account requirements as defined in 5.2.2

to 5.2.5.

Table 3 The of Glass Fibers Used as the Reinforcement of FRP Tanks

Glass Fiber Types Maximum Temperature, C (F)

E Alumina-borosilicate glass, 1% Alkali content

E-CR Alumina-limesilicate glass, 1% Alkali content

AR Zirconium-lime glass, 15% Zirconium content

A Alkali-lime glass, 15% Alkali content

C Alkali-lime glass, 8% Alkali content

5.3.2 Surface Nonwovens Fabric (Veils)

a) The surface nonwoven fabric supplier shall state the material

filament structure, binder, sizing and mass per unit area and its

compatibility with the resin system and the laminating process.

b) Surface nonwovens fabric shall be made from filaments of textile

glass or textile of synthetics, e.g., polyacrylonitrile, polyamide,

polyester or of carbon fibers, with or without orientation, and

having mass per unit area between 20 to 55 g/m. Typical veil

materials used in the corrosion resistance barrier are:

Glass Surfacing Veil. C-Glass surfacing veil, 0.25 mm (10 mls) thick, with a silane-type finish and a binder compatible with the

lay-up resin.

Organic Surfacing Veil. Organic surfacing veil, apertured or non-apertured polyester veil, 0.3 to 0.4 mm (12 to 16 mls)

thick, with a finish compatible with the lay-up resin.




Page 13 of 29

Carbon Surfacing Veil. Carbon surfacing veil, 20 g/m2 (0.6 oz/yd

2), 0.15 mm (6 mls) thick, with a finish compatible

with the lay-up resin.

c) Surface nonwovens fabric shall be in accordance with the

specification of the supplier. The material data sheets shall state

the name, identity mark, material, type of filament, binding and the

properties.

d) The tank manufacturer shall verify that the surface nonwoven

fabric conforms to the property values of mass per unit area,

thickness and tensile strength as established in the fabric data sheet.

5.3.3 Chopped Strand Mats

a) The chopped strands mat supplier shall state the strand, structure,

binder and mass per unit area, the compatibility with the resin

system, the laminating process and the laminate design.

b) Chopped strand mats shall be made of textile glass strand, cut from

25 to 50 mm in length, without orientation of strands, and mass per

unit area within 225 to 600 g/m2. Chopped strands mat typically

used are type E (electrical borosilicate) or ECR (electrical corrosion-

resistant) glass; 236, 354, or 472 g/m2 (0.75, 1, or 1.5 oz/ft

2), with a

silane-type finish.

c) The material data sheets the material provided by supplier shall

state the name, identity mark and properties of the chopped strand

mats in accordance with ISO 2559 or equivalent.

d) The tank manufacturer shall verify that the chopped strand mat

conforms to the property values of mass per unit area, thickness

and tensile strength as established in the chopped strand mat data

sheet.

5.3.4 Woven Fabrics/Woven Roving Fabrics

a) Fabric shall be made of glass yarns or rovings. The fabric supplier

shall state the grade of yarns or roving, structure, finish and mass

per unit area and the compatibility with the resin system, the

laminating process and laminate design.

b) The fabric supplier shall state the linear density of yarns or rovings,

by ratio of mass of warp to weft, bidirectional or unidirectional.

Mass per unit area shall be within 240 to 1,200 g/m2. Woven

roving could be E glass, nominal 813 g/m2

(24 oz/yd2), 5 x 4 square

weave, with a silane-type finish.




Page 14 of 29

c) The Fabric shall be in accordance with ISO 2113 or equivalent.

d) Special fabrics, e.g., combined chopped strand mat/woven fabrics

or multi axial fabrics may be used in accordance with the

requirements of the European Standard EN 13121.

e) The individual material data sheets of the fabrics provided by the

material supplier shall include the name, identity mark and

properties in accordance with ISO 2113 or equivalent.

f) The tank manufacturer shall verify the fabric conforms to the

property values of mass per unit area, thickness and tensile strength

as established in the fabric data sheet.

5.3.5 Rovings for Winding and for Chopping Applications

a) Rovings shall be made of glass textile. The rovings supplier shall

state the grade of filament, linear density and sizing and as well as

the compatibility with the resin system, radial or helical winding

process and the laminate design.

b) Rovings for filament winding or for chopping applications shall be

specified by their linear density and sizing agent.

c) Rovings for filament winding or for chopping applications shall be

in accordance with ISO 2797 or equivalent.

d) The individual material data sheets of the roving provided by the

material supplier shall include the name, identity mark and

properties in accordance with ISO 2797 or equivalent.

e) The tank manufacturer shall verify the roving conforms to the

property values of linear density, filament diameter, type of sizing

and tensile strength as established in the roving data sheet.

5.4 Additives

5.4.1 General

a) The representative properties of any additive used shall be stated.

b) If any additives are incorporated into the resin system by the

manufacturer of the tank, the manufacturer shall inform the

purchaser of the inclusion of any such additives before manufacture

commences.

c) The additives shall be used in accordance with the resin and/or

additive supplier's recommendations.




Page 15 of 29

5.4.2 Thixotropic Agents

Thixotopic agents such as fumed silica may be added to the resin up to

5% by mass, using a high shear stirrer, for viscosity control, provided it

does not interfere with visual inspection.

5.4.3 Conductive Fillers

a) Conductive fillers such as graphite or carbon black may be added

to the resin in order to meet any requirements for electrical

conductivity of the laminates. Such fillers may also be used in

conductive pastes used to facilitate spark testing of welds in

thermoplastics linings.

b) Conductivity can also be achieved by the utilization of carbon fiber

or other conductive fibers.

5.4.4 Fire Retardants

Fire retardants such as aluminium trihydrate or antimony oxides may be

added to specified laminate layers to meet certain requirements for fire

resistance. No fire retardants other than those present in the fire

resistance test sample will be allowed to be used during fabrication of the

tank(s). The tank manufacturer shall demonstrate that the incorporation

of the fire retardant additives will not negatively affect the mechanical

and physical material properties.

Special intumescent coatings can also be utilized to improve the fire

resistance of the material utilized to manufacture the tank.

5.4.5 Paraffin Wax

a) The final layer may contain paraffin wax in order to meet

requirements for surface cure.

b) The wax should have a melting point of 40 to 60C and should be

added to the resin in the form of a 10% solution in styrene so as to

achieve a wax content of 0.2 to 0.8% by mass.

5.4.6 Aggregates and Fillers

Neither aggregates (inert granular material) nor other inert fillers shall be

incorporated into the laminate structure. Fillers may be used to

formulate resin pastes.




Page 16 of 29

5.4.7 Ultraviolet Absorbers

When required, ultraviolet absorbers may be incorporated into the

laminate or outer layers, in accordance with the supplier's

recommendations (usually used at a level of less than 0.5% by mass).

5.4.8 Pigments

Pigments are permissible only in the outer resin surface and - if required

- shall be applied after visual inspection has been carried out.

5.4.9 Paints and Coatings

Polyurethane based coating systems can be applied on the external

surface of the tank - if required - and shall be applied after visual

inspection has been carried out.

5.4.10 Surface active agents

Surface active agents may be added to the resin to improve its

processability. Examples of this type of additive are those used as air

release agents, wetting agents, activators for thixotropic agents and

monomer emission suppressants.

5.5 Thermoplastic Lining Materials

5.5.1 General

a) Lining materials shall be selected from the following thermoplastics:

Polyvinylchloride in accordance with EN 13121-1 or ASME RTP-1

PVC-U

Chlorinated Polyvinylchloride in accordance with ASME RTP-1

CPVC

Polypropylene (homo, block and random polymers) in accordance with

EN 13121-1 or ASME RTP-1

PP-H, PP-B, PP-R

Polyvinylidene fluoride in accordance with EN 13121-1 or ASME RTP-1

PVDF

Ethylene-chlorotrifluoroethylene copolymer in accordance with


E-CTFE

Fluorinated ethylene-propylene copolymer in accordance with

FEP




Page 17 of 29


Perfluoro-alkoxy copolymer in accordance with EN 13121-1 or

ASME RTP-1

PFA

Ethylene-tetrafluoroethylene in accordance with ASME RTP-1

ETFE

Polytetrafluoroethylene in accordance with ASME RTP-1

PTFE

High Density Polyethylene in accordance with ASME RTP-1

HDPE

b) The lining material shall be selected on the basis of its ability to meet

the requirements for service conditions including permeability,

environmental stress cracking, mechanical properties, bond strength

to laminate and fabricability (forming, welding) per EN 13121-2 and

EN 13121-3, or ASME RTP-1.

c) All parts of the lining shall be manufactured from the same grade of

material.

d) The thermoplastic lining supplier shall state that the specific linings

meet the chemical resistance requirements given in EN 13121-2.

e) When required, flammability and electrical conductivity shall be

taken into account.

5.5.2 Liner Thickness

a) The liner will be thick enough so that permeation will be low to

minimize FRP structure chemical exposure. However, the liner will

not be too thick that anticipated forming processes during fabrication

will cause damaging stresses and possible failure.

b) The required thickness for the thermoplastic liners is shown in

Table 4.

Table 4 Required Thickness of Thermoplastics Liners

Material Thickness of Sheets, mm

PVC-U 3.0 to 4.5

CPVC 3.0 to 4.5

PVDF 2.4 to 4.0

PP-H,-B,-R 3.0 to 6.0




Page 18 of 29

Material Thickness of Sheets, mm

E-CTFE, FEP, PFA, ETFE 1.7 to 2.5

PTFE 2.5 to 4.0

HDPE 3.0 to 6.0

5.5.3 Mechanical and Thermal Properties

a) The lining material properties shall conform to the results of the

properties outlined in values given in Table 5.

b) The actual results shall be stated by the supplier of the lining

material.

c) The tank manufacturer shall verify that the liner material conforms

to the property values of dimensions, mechanical and thermal

properties as established in Table 5.

5.5.4 Welding consumables

All welding rods shall be of the same or compatible grade of material of

the lining and shall not impair the performance of the lining.

5.5.5 Dimensional stability

In order for the lining to retain its dimensional stability during heat

forming and welding, the thermoplastic lining material shall conform to

the requirements for heat reversion as specified by the material supplier.

Table 5 Properties of the Thermoplastic Sheet Material[1]

Material

Type

Density

ISO 1183

Vicatb

softening

Temperature

EN ISO 306

Tensile

Strength at

Break

EN ISO

527-2

Tensile

Strain at

Break

EN ISO

527-2

Modulus of

Elasticity in

Tension

EN ISO

527-2

Shore D

Hardness

EN ISO 868

Heat

Deflection

Temperature

EN ISO 75-

2c

Linear

Thermal

Expansion

ISO 11359-

2

(g/cm3) (C) (MPa) (%) (MPa) (C) (C)

PVC-U 1.45 75 55 15 3000 80 75 75

CPVC 1.50 --- 55 15 3000 --- 102 120

PP-H 0.91 --- 30 > 50 1200 65 50 180

PP-B 0.91 --- 20 > 50 700 60 45 180

PP-R 0.91 --- 20 > 50 700 60 45 180

PVDF 1.78 145 50 80 2000 80 90 130

E-CTFE 1.69 115 45 200 1700 75 75 80

FEP 2.15 70 25 300 350 55 50 100

PFA 2.15 75 30 300 300 60 60 140

ETFE 1.70 --- 45 250 1656 --- 104 80

PTFE or TFE 2.1-2.3 --- 20 250 450 --- 221 120




Page 19 of 29

HDPE 0.95-0.97 --- 22-31 >500 1100 --- 85 150 a method MFR 190/5

b method VST/B

c method A

[1]: Relevant ASTM standard test methods shall be used for suppliers following ASTM/ASME documents.

6 Laminate Requirements

6.1 General

The laminate properties specified in this section will be used as baseline for the

quality control test to be conducted on the final material produced during the

manufacture of the tank. The quality control tests should be carried out

according to Section 7 of this specification.

If the laminate properties are defined by conducting tests from prototype

samples, these tests can be conducted by the liner supplier, tank manufacturer or

independent testing laboratory.

The quality of lamination work depends on the skill, knowledge and experience

of the laminator. Periodic assessment of the skill of the laminator is essential for

the assurance of the quality of the lamination work. The methodology to assess

the the knowledge and skills of laminators who are required to carry out work on

FRP tanks is described in ASME RTP-1 Mandatory Appendix M-5 or

EN 13121-3 Annex E. All laminators shall have documented experience as a

laminator or have completed a training course. The tank manufacturer shall

demonstrate that their laminators have been trained and certified by either of the

assessment procedures mentioned above.

6.1.1 Chemical Protective Barrier

6.1.1.1 General

The chemical protective barrier shall be selected in accordance

with the requirements of EN 13121-2. The chemical barrier

construction shall not be considered in any strength, or stability

calculation.

6.1.1.2 Corrosion-Resistance Barrier (Resin Based)

Laminates shall consist of a resin based corrosion-resistant

barrier (comprised of an inner surface and an interior layer) and

a structural layer. The reinforcement content of the corrosion

barrier shall be between 20% to 30% by weight.




Page 20 of 29

a) Inner Surface. The inner surface exposed to the fluids

shall be a resin rich layer reinforced with a surfacing veil

providing a thickness of 0.25 mm to 0.5 mm (0.01 in. to

0.02 in). The surface veil (VL) may be either C glass,

synthetic veil, carbon fiber or ECR glass.

b) Interior Layer. The inner surface layer, which is exposed

to the service fluids of the tank shall be followed with an

interior layer. This layer is composed of resin reinforced

with noncontinuous glass fiber strands (25.4 mm to

50.8 mm long), applied in a minimum of two plies

totaling a minimum of 450 g/m2. These plies shall be

layers of chopped strand mat and/or chopped roving.

Each ply of mat or pass of chopped roving shall be well

rolled to thoroughly wet out the reinforcement and

remove entrapped air prior to the application of additional

reinforcement. The combined thickness of the inner

surface and interior layer shall not be less than 2.5 mm.

The corrosion-resistant barrier is to exotherm and cool

before the structural layer is applied.

6.1.1.3 Thermoplastic Liners

a) The thermoplastic liners shall be fabricated according to

the requirements of ASME RTP-1 Mandatory Appendix

M-12.

b) The selected thermoplastic liner shall be included in the

analysis, but will not be considered to add to the overall

strength of the structure of the tank.

c) The tank manufacturer shall supply the liner properties

and documents with the design package, including:

Liner thickness and properties according to Tables 4 and 5 of this specification.

Weld procedures for the different thermoplastic liners.

The welders shall be qualified according to the requirements of ASME RTP-1, Article H of the

Mandatory Appendix M-12; or EN 13121-3, Annex F.

The tank manufacturers shall hold the qualification

reports for all the thermoplastic liner welders.

Thermoplastic weld strength tested according to




Page 21 of 29

ISO 527-2 or ASTM D638.

Bend tests for welds in thermoplastic when tested according to the test method described in Annex D.4

of EN 13121-3.

Lap shear strength of bond between thermoplastics liner and laminate when tested according to the test

method described in Annex D.8 of EN 13121-3.

The minimum bond shear strengths for thermoplastic

liners are shown in Table 6.

Table 6 Minimum Bond Shear Strengths for Thermoplastics Linings

Property Shear Strength, N/mm

PVC-U 7.0

CPVC 7.0

PVDF 5.0

PP-H,-B,-R and HDPE 3.5

E-CTFE, FEP, PFA, ETFE, PTFE 5.0

Peel strength to establish the bond strength between liner and laminate when tested according to the test

method described in Annex D.9 of EN 13121-3.

d) The thermoplastic liner supplier shall state that the liner

meet the chemical resistance requirements given in

EN 13121-2.

6.1.2 Structural Layer

a) The physical and mechanical properties of the laminate(s) which

will be used in the fabrication of the different shells of the

composite tank shall be provided by the tank manufacturer.

These laminates shall have the following glass content by mass:

Chopped strand mat (CSM) laminates: 25% to 35%;

Woven roving (WR) laminates: 45% to 55%;

Filament wound (FW) laminates: 60% to 75%.

b) The minimum specified properties shall be supplied by the tank

manufacturer in the design package for each wall construction of




Page 22 of 29

the tanks, body shell, bottom and top head. The properties are

defined below.

% of glass content (loss on ignition) according to the test method of ASTM D2584;

Tensile modulus of laminate according to the test method of ASTM D638 or ASTM D5083;

Ultimate tensile strength according to the test method of ASTM D638 or ASTM D5083;

Inter-laminar shear test (based on max. shear load over a specified shear length) according to the test method describe in

Annex D.7 of EN 13121-3;

Barcol hardness test according to ASTM D2583 test method;

Short term creep test according to the test method described in Annex D.10 of EN 13121-3;

Flexural strength of laminate according to ASTM D790 test method.

Flexural modulus of laminate according to ASTM D790 test method.

These properties can be specified according to the results shown in

ASME RTP-1, Table 2A-3 or Mandatory Appendix M-3, EN

13121-3 Table 3, or tests carried out by tank manufacturer or

independent and certified testing laboratory.

c) In acid services such as H2SO4, HCl, HNO3, only ECR glass

reinforcing fibers shall be utilized for the manufacturing of the

structural layer.

d) When thermoplastic lining material is utilized, additional tests as

specified in with Section 6.1.1.3 of this specification shall be

carried out.

6.1.3 Outer Surface

a) The outer surface of the finished laminate shall be a separately

applied paraffinated (waxed) resin coat that, when cured, passes the

acetone test per ASTM C 582, Section 9.2.2. This outer surface

coat shall either be applied over the final mat ply of the structural

layer or over an additional resin-rich layer when required by

Section 6.1.3(b) of this specification.




Page 23 of 29

b) When the outer surface will be subjected to spillage or a corrosive

environment, a resin-rich layer, in accordance with Section 6.1.1.2

of this specification, shall be applied over the final mat ply of the

structural layer prior to the application of the paraffinated (waxed)

resin coat in Section 6.1.3(a) above.

c) Provisions are required to minimize ultraviolet degradation of the

laminate surface. Methods include use of ultraviolet absorbers,

screening agents, or resins resistant to ultraviolet degradation,

polyurethane coatings or incorporation of pigment of sufficient

opacity in the paraffinated resin coat. Since pigmentation makes

laminate inspection difficult, the resin-rich layer shall be applied

only after the laminate has been inspected.

d) Where the final lay-up is exposed to air, full surface cure shall be

obtained by applying to the final layup a coat of paraffinated

(waxed) resin that, when cured, passes the acetone test per

ASTM C582, Section 9.2.2. Other techniques such as sprayed,

wrapped, or overlaid films are also acceptable methods to attain

surface cure, provided the surface resin under the film passes the

acetone test.

6.1.4 Heat Deflection Temperature (HDT)

a) The heat deflection temperature of cured resin system used for the

reinforced laminate shall be at least 20C higher than the design

temperature of the FRP tank.

When Design Temperature (TS) 60C; (HDT 82C)

When Design Temperature (TS) > 60C; (HDT - 40 C) TS

b) Only resins with HDT of at least 82C (180F) per ASTM D648

with a 1.8 MPa (264 psi) loading and a 3.2 mm (18 in) specimen shall be used.

6.1.5 Flammability

When required or specified, the external surface layer(s) of the tank shall

be modified to fulfill the required surface spread of flame characteristic.

The material shall show flame spread rating from 0 to 25 which

represents Class 1 rating for fire resistant material per ASTM E-84.

6.1.6 Electrical Resistivity

Where the build-up of static electricity may cause problems, the surface

resistivity of those parts of the tank or vessel in contact with the fluid




Page 24 of 29

shall not exceed 106 , or the volume resistivity 106 m, when tested in

accordance with ISO 3915 test method.

6.1.7 Post-Curing

a) If required by design, the FRP tank manufactured following this

specification should undergo a thermal post-curing treatment using

hot air or similar heating system. This treatment, which must be

carried out at controlled temperature and time, has the aim of

perfecting the crosslinking of the resin, guaranteeing the very best

chemical and mechanical performance of the tank.

b) The tank manufacture shall have written procedures for the post-

curing process of the FRP tank.

c) Recommended timings and temperatures are summarized in Table 7.

Table 7 Recommended Post-curing Schedule for FRP Tanks

Type of Resin Temperature

C Time

Hours

Polyester - Isophtalic 70 (-3/5) 6 (-1/+2)

Polyester - Bisphenol 70 (-3/5) 10 (-1/+2)

80 (-3/5) 6 (-1/+2)

Vinylester 70 (-3/5) 12 (-1/+2)

80 (-3/5) 8 (-1/+2)

7 Inspection and Quality Assurance Requirements

Quality control records required by this specification shall be legible, identifiable,

retrievable and protected from damage, deterioration, or loss. These records shall be

retained by the tank manufacturer for a minimum of five years following the date of

manufacture. All quality control records required by this specification shall be signed

and dated, as established by the manufacturer's procedures.

7.1 Raw Materials

7.1.1 Matrix Material: Resin and Curing Agent

a) This section specifies the minimum requirements for the

inspections and tests that are to be performed by the tank

manufacturer or an independent testing laboratory on resins and

curing agents (curing agents include accelerators, promoters, and

peroxides as required for specific resin systems) according to the

requirements of ASME RTP-1 Mandatory Appendix M-2.




Page 25 of 29

b) The requirements of this section shall be accomplished prior to

acceptance of resins and curing agents for fabrication of tanks to

this Specification. These requirements will help ensure that the

resins and curing agents are correctly identified; meet the

manufacturers specification; and are suitable for proper fabrication, curing practice, and design requirements of tanks

fabricated to this Specification.

c) The following tests shall be conducted on resins and curing agents;

Visual Inspection, Specific Gravity, Viscosity using Gardner-Holdt

Method or Brookfield Method, and Gel Time at room temperature.

d) These tests shall be performed on one random sample from each lot

or batch of material received from a supplier. If any containers or

packages are damaged, then the contents of each damaged

container shall be rejected.

7.1.2 Reinforcing Material


inspections and tests that are to be performed by the tank

manufacturer or an independent testing laboratory on reinforcing

materials according to the requirements of ASME RPT-1

Mandatory Appendix M-1.

b) The requirements of this section are to be accomplished prior to

acceptance of reinforcement for fabrication of tanks to this

Specification.

c) These inspections shall be performed on one random sample from

each lot or batch of reinforcing material received from a supplier.

If any containers or packages are damaged, then the contents of

each damaged container shall be rejected.

7.1.3 Thermoplastic Liners


inspections and tests that shall be performed by the tank

manufacturer or an independent testing laboratory on thermoplastic

liners according to the requirements of ASME RPT-1 Mandatory

Appendix M-12.

b) These inspections are to be performed on one random sample from

each lot or batch of material received from a supplier. If any

containers or packages are damaged, then the contents of each

damaged container shall be inspected according to section 7.1.3.a




Page 26 of 29

of this specification. The requirements of this section are to be

accomplished prior to acceptance of liner for fabrication of tanks to

this Specification.

c) The weldability of the thermoplastic material is to be performed on

one random welded sample from each lot or batch of material

received for the sheets as well as for the welding consumables.

7.2 Quality Control test on Laminates

a) This section specifies the minimum requirements for the inspections and

tests that are to be performed by the tank manufacturer or an independent

testing laboratory on the laminate according to the requirements of

Section 6.1.2 of this specification.

b) The tank manufacturer shall verify that the laminate was fabricated

according to a given design parameters and drawings. The following

inspections and tests should be conducted according to ASME RTP-1 Part 6.

Resin cure. The test shall be conducted on the internal and external surfaces of the tanks according to ASME RTP-1/Section 6-910.

Barcol hardness shall not be lower than 90% of the value specified by

the resin supplier for a clear resin casting and according to the value

specified in Section 6.1.2.

Dimension and Laminate thickness checks are in accordance to ASME RTP-1 / Section 6-920.

Physical Property and Laminate Reinforcing Content Tests. These tests shall be conducted in accordance to ASME RTP-1/

Section 6-930. The Manufacturer is responsible for producing

laminates that will meet or exceed permissible physical and mechanical

properties used in the design and as are established as minimum within

Section 6.1.2. The physical and mechanical property average value

minus two standard deviations shall be higher than the specified value

given in Section 6.1.2. Laminates shall also be in accordance with the

reinforcing sequence and minimum reinforcing content established in

Section 6.1.2. The physical and mechanical properties shall be verified

from the tank cutout samples.

Glass content (loss on ignition)

Number of layers of glass, type and arrangement

Tensile modulus of laminate

Ultimate tensile strength




Page 27 of 29

Inter-laminar shear test

Short term creep

Flexural strength of laminate

During fabrication, the manufacturer shall perform all such checks necessary to assure that laminate imperfections as defined in

ASME/RTP-1 Table 6-1 are within the requirements of this

Specification. Visual Inspection Acceptance Level shall be conducted

in accordance to the critical level services defined for the tank

application.

Where a thermoplastics liner is used, the mechanical property average values minus two standard deviations shall be higher than the specified

value given in Section 6.1.1.3 of this specification;

Lap shear strength

Peel strength

Note: If the tests cannot be conducted on samples machined from the FRP tanks cutouts (e.g., tank bottoms), the tank manufacturer shall fabricate at the same time the non-testable component is being made, a laminate piece, using the same materials as those being used for the non-testable component, this includes but is not limited to resin system, fiber amount and arrangement, and the same curing characteristics. This laminate piece shall be sufficiently sized such that all samples which would have been machined from a tank cut out can be obtained from the laminate piece.

8 Documentation

8.1 Documentation Provided by the Owner

The full information that shall accompany a purchase order for composite tank

as the Users Basic Requirements Specification, ASME RTP-1, Table 1.1.

8.2 Documentation Provided by the Tank Manufacturer

The tank manufacturer shall provide the Purchaser with a written description of

the composite tank system. As a minimum, this will include:

Fabricators Data Report

Drawings, including all tank dimensions, thickness, fitting and accessories locations, etc.

Definition of all raw material properties as established in Section 5 and




Page 28 of 29

certified as required in Section 7.1, including tests report forms for all tests

performed on all lots or batches of materials used during fabrication.

Physical and Mechanical properties values utilized during the design as described in Section 6.1.2.

Physical and Mechanical properties values determined according to Section 7.2. of this specification.

Minimum and maximum operating temperatures.

Limitations with respect to chemical exposure.

Revision Summary

1 November 2011 New Saudi Aramco Materials System Specification.




Page 29 of 29

Appendix A Workflow for the Material Selection and Testing of FRP Tanks

Users Basic Requirements Specification (UBRS)ASME RTP-1

By: Owner/ Design Engineer

Raw Materials Selection

Section 5, 32-SAMSS-037

By: Design Engineer/ Manufacturer

Material Parameters/ Data Sheet used in

Design of Laminate

Section 6, 32-SAMSS-037

By: Manufacturer

Revise/ Approve Material Selection

Sections 5 and 6, 32-SAMSS-037

By: Manufacturer

Tank Design

32-SAMSS-002

By: Manufacturer

Tank Manufacture

By: Manufacturer

Quality Control Test Raw Materials

Section 7.1, 32-SAMSS-037

By: Manufacturer

Quality Control Test Laminate

Section 7.2, 32-SAMSS-037

By: Manufacturer

Quality Control test Tank

32-SAMSS-002

By: Manufacturer

New Batch

Raw Materials

Tank Rejection

Yes

No

Yes

Yes

No

No

Appendix A Flowchart for Material Selection Criteria and Qualification Testing

Figure A Workflow for the Material Selection and Testing of FRP Tanks

32-SAMSS-037

Documents

material specification

testing of materials

raw materials

references material

testing of frp tanks

copyrightsaudi aramco

stationary tanks

industry standards